Field of Invention
The present invention belongs to the field of low-dimensional materials and advanced materials, and particularly relates to a preparation method of a graphene nanoribbon on h-BN (hexagonal boron nitride (h-BN)).
Description of Related Arts
Graphene has become a popular research issue in science and industry due to its superior nature in physical-chemical properties, and is expected to be a significant building-block material in the new generation of micro-nano electronic devices due to its superior electronic transport characteristics and clipping manufacturing characteristics. However, the property of the current graphene is subject to the preparation method and means, and the application thereof is thus limited. At present, the commonly used method for preparing a graphene includes a mechanical stripping method, a chemical vapor deposition method (CVD), a SiC epitaxial growth method and a graphite oxidation-reduction method and the like, wherein, the CVD method has become the quickly developed and the most popular preparation method as a result of low cost, easy large-scale production and compatibility with semiconductor technology. However, the CVD method is catalytic growing a graphene on a transition metal, but fails to be directly applied in the preparation of electron devices, while it is required to transfer the graphene to a dielectric layer to achieve an effective assembled device. At present, SiO2/Si is adopted in most dielectric layers of the studied graphene photoelectric devices. Researchers has pointed out that, due to the localized carrier doping of the graphene caused by charge impurities of the SiO2 surface, and the scattering effect of the phonons in the SiO2-graphene interface to the graphene carriers, an upper limit of the electronic mobility of the graphene is dropped to 40000 cm2/Vs, which is far below the theoretical value of an intrinsic graphene, thereby decreasing the applications of the graphene. Besides, the transfer process of the graphene adopts a wet chemical method, which not only complicates the technological process, but also inevitably causes a damage and contamination to graphene lattice and thus reduces the quality of the graphene, thereby penalizing the preparation of high-performance electron devices. Therefore, it has become one of the key problems in graphene photoelectric device on how to avoid the transfer and to overcome the defect of SiO2/Si substrate.
Moreover, the special crystal structure of the graphene leads to its distinctive zero-energy gap structure, while its metallic characteristic fails to be directly applied in the preparation of electron devices. Currently, though it is able to prepare graphene of relative few defects and complete structure, but the band gap of the obtained graphene is almost zero or quite small, which can hardly meet the requirements for semiconductor functional devices. Nevertheless, the application of the graphene is limited in the electronics field due to its zero-band gap structure. The theoretical and experimental research show that, energy gap of graphene nanoribbon possesses width dependent effect due to the quantum confinement effect and edge effect that graphene nanoribbon possesses. Results of the experimental research show definitely that the energy gap increases with the width decrease of the nanoribbon. Therefore, it is of great significance to develop the regulation of the electronic structure of the graphene and the confinement band gap technology. In terms of chemistry and physics, researchers have proposed a preparation method for modifying the graphene, an etching method or an external electric field regulation method directed at the geometric structure size and geometric structure of the graphene; or chemical methods, such as an edge modification method or a chemical doping method, all of which may open the band gap of the graphene to some extent. However, in those methods for regulating the electron structure of the graphene, it is required to prepare a graphene of complete structure, followed by performing modified regulation, which is subject to a restriction of process technology, and a non-control of doping concentration, etc. Also, from an electron device manufacture and a commercialization perspective, the process is tedious and is high in cost.
From the above, the development of the graphene faces the following challenges: its application in the field of nanoelectronic device and integrated circuits is limited by the electron structure of the zero-band gap of the graphene; the electrical property of the graphene material is far inferior to its intrinsic electrical property because of the introduction of defects and electric charge impurities in the existing preparation and transfer technology of graphene. Therefore, the present invention provides a preparation method of a graphene nanoribbon on h-BN, to overcome the bottlenecks in the current development of the graphene.